How to efficiently remove a query string by Key from a Url?

Question

How to remove a query string by Key from a Url?

I have the below method which works fine but just wondering is there any better/shorter way? or a built-in .NET method which can do it more efficiently?

 public static string RemoveQueryStringByKey(string url, string key)         {             var indexOfQuestionMark = url.IndexOf("?");             if (indexOfQuestionMark == -1)             {                 return url;             }              var result = url.Substring(0, indexOfQuestionMark);             var queryStrings = url.Substring(indexOfQuestionMark + 1);             var queryStringParts = queryStrings.Split(new [] {'&'});             var isFirstAdded = false;              for (int index = 0; index <queryStringParts.Length; index++)             {                 var keyValue = queryStringParts[index].Split(new char[] { '=' });                 if (keyValue[0] == key)                 {                     continue;                 }                  if (!isFirstAdded)                 {                     result += "?";                     isFirstAdded = true;                 }                 else                 {                     result += "&";                 }                  result += queryStringParts[index];             }              return result;         } 

For example I can call it like:

  Console.WriteLine(RemoveQueryStringByKey(@"http://www.domain.com/uk_pa/PostDetail.aspx?hello=hi&xpid=4578", "xpid")); 

Hope the question is clear.

Thanks,

Answer 1

This works well:

public static string RemoveQueryStringByKey(string url, string key) {                        var uri = new Uri(url);      // this gets all the query string key value pairs as a collection     var newQueryString = HttpUtility.ParseQueryString(uri.Query);      // this removes the key if exists     newQueryString.Remove(key);      // this gets the page path from root without QueryString     string pagePathWithoutQueryString = uri.GetLeftPart(UriPartial.Path);      return newQueryString.Count > 0         ? String.Format("{0}?{1}", pagePathWithoutQueryString, newQueryString)         : pagePathWithoutQueryString; } 

an example:

RemoveQueryStringByKey("https://www.google.co.uk/search?#hl=en&output=search&sclient=psy-ab&q=cookie", "q"); 

and returns:

https://www.google.co.uk/search?#hl=en&output=search&sclient=psy-ab 

Answer 2

    var queryString = "hello=hi&xpid=4578";     var qs = System.Web.HttpUtility.ParseQueryString(queryString);     qs.Remove("xpid");     var newQuerystring = qs.ToString(); 

This still works in .NET 5.